Apparatus for spreading hot asphalt



Oct. 10, 1933.

J. F. GALLAGHER 1,930,309 APPARATUS FOR SPREADING HOT ASPHALT Filed Nov. 14, 1930 J FZ Z Patented Oct. 10, 1933 UNITED STATES APPARATUS FOR SPREADING nor ASPHALT James F. Gallagher, Chicago, Ill.

Application November 14, 1930 Serial No. 495,567

3 Claims.

In constructing asphalt roads, considerable manual labor is required in' spreading out and leveling off the asphalt, owing to the fact that the asphalt is hot and tends to stick and gum up on any cold surfaces with which it comes into contact. Ordinary mechanical screeds, such as are used successfully in the spreading and leveling of concrete, have been tried out on asphalt, with unsuccessful results. 7

The object of the present invention is to provide a novel screed which will successfully operate against hot asphalt and other materials and mixtures which are difficult to spread.

Other more specific objects and advantages of the invention will be apparent upon a full understanding of the construction, arrangement and operation of the novel screed.

One form of the invention is presented herein by way of exemplification, but it will of course 26 be appreciated that the invention is susceptible of embodiment in other structurally modified forms coming equally within the scope of the appended claims.

In the accompanying drawing:

Fig. l is a front view of the apparatus of the invention;

Fig. 2 is a rear view of the screed member, with certain portions broken away for clearness; and

Fig. 3 is a cross section through the screed 80 member, taken on the line 33 of Fig. 2.

As will be observed in the drawing, the screed of the invention, which is designated by the numeral 10, is attached to the front end of a power driven frame 11 of ordinary construction,

which frame spans the road area 12 to be surfaced and is supported on flanged wheels 13 which ride on rails 14 at the sides of the road. The lower front edge 15 of the screed is shaped to produce the crowning desired for the road, adjustably positioned plates 16 being preferably provided on the front face of the screed for that purpose.

The screed 10, in the particular form shown, is a long hollow sheet metal member of L-shaped cross section. The hollow interior of the screed is filled with any easily obtainable and inexpensive liquid 16 which will not volatilize appreciably when moderately heated. The liquid is circulated through the screed by means of a power-operated pump 18. The intake side of the pump is connected with a pipe 19 which opens into the hollow interior of the screed near the bottom of the latter, while the pressure side of the pump is connected with a coiled pipe 20 which is in turn connected with two branch pipes 21 and 22 which open into the upper portion of the interior of the screed near the ends thereof. The screed is closed except for a shielded vent 23 in the center of the top of the same.

The coiled portion of the pipe 20 is enclosed within a housing 24 on the screed and is heated by a blowtorch 25 which is positioned on the screed in registration with an opening 26 in one end of the housing. A Valve 27 is located in the pipe 20 between the coiled portion of the latter and the pump for diverting the pumped liquid from the system into a pipe 28 when the system isto be emptied. If the liquid is to' be saved for subsequent use, the pipe 28, before the valve 27 is turned to divert the liquid into such pipe, is connected up with a fiexible hose leading to a barrel or other suitable storage receptacle.

The screed is prepared for use by filling the hollow interior thereof with oil or other suitable liquid and starting the pump and blowtorch. As the liquid circulates through the coiled pipe and is played upon by the torch, it becomes heated and transmits its heat to the front and bottom surfaces of the screed uniformly throughout the length of the same. As soon as such surfaces have been heated up to a temperature anywhere from 150 to 350 degrees Fahrenheit, depending upon the character of the material to be spread, the torch is adjusted to maintain that temperature and the screed is then ready to be brought into engagement with the hot asphalt. The torch may be even turned off, since the liquid, being in considerable volume, will maintain the front and bottom surfaces of the screed in a heated condition for quite a long period of time. Because of the heated .condition in which the screed is maintained, the asphalt will not stick to the latter to any appreciable extent and the screed may be used quite effectively to spread and level out the asphalt. The heated bottom surface of the screed will also have somewhat of a calendering effect upon .the upper surface of the leveled asphalt, leaving the latter practically in condition for rolling. It will also have acom- J pacting effect on the asphalt, the front portion of the bottom surface of the screed being preferably curved upwardly a little at 29 to accomplish this. The screed of the invention, in addition to being used to initially spread out the asphalt or other material, may be used to subsequently correct inequalities in the finished surface, either before or after the ordinary rolling operation, by being brought into position again over the surface and allowed to remain in such position long enough to permit the desired addition or removal or material.

While the screed of the invention is intended primarily for use in connection with the spreading, compacting and leveling of hot asphaltic mixtures, it may be used equally as well with cold asphaltic mixtures and with other hot or cold bituminous mixtures which tend to adhere to cold surfaces. In view of this, the word asphalt" as used in the foregoing description and in the following claims is intended to include within its definition all such materials.

I claim:

1. Asphalt spreading apparatus, comprising, in combination, a wheeled frame, an elongated screed of hollow construction mounted on the frame crosswise of the latter, and a pump for circulating a hot fluid through the screed substantially throughout the length or the latter to heat the front and bottommurfaces thereof.

2. Asphalt spreading apparatus, comprising, in combination, a wheeled frame, an elongated screed of hollow L-shaped cross section mounted on the frame crosswise of the latter with the upstanding portion of the screed arranged foremost to contact with the asphalt, a pump for circulating a liquid through the screed throughout the length of the latter to heat the front and bottom surfaces thereof, and means for heating the liquid at one point, in its circulation.

3. Asphalt spreading apparatus, comprising, in combination, a wheeled frame, an elongated hollow screed mounted on the frame crosswise of the latter, a hot liquid within said screed, a circulatory system for said liquid without said screed adapted to contain a relatively small portion of the liquid at any one time, and means along said circulatory system to heat the liquid contained therein.

JAMES F. GALLAGHER. 

